1. Field of the Invention
This invention relates to tools for servicing internal combustion engines and more particularly, to a valve positioning device for supporting valves in communication with valve seats within a cylinder head and piston sleeve assembly of the type having a flanged base.
2. Description of the Prior Art
The owners of aircraft of the type having overhead valve, internal combustion engines are required by FAA safety regulations to make considerable monetary investments in periodically having these engines dismantled, inspected and rebuilt. The charges for rebuilding such an engine are highly labor intensive because a highly skilled, certified A & E (aircraft and engine) mechanic must perform, or at least supervise, all of this work. Therefore, the introduction of a labor saving device to be used in this process should result in a considerable savings to any A & E mechanic who specializes in rebuilding these engines.
One particularly time-consuming task in the complex process of rebuilding an aircraft engine involves the removal and reinsertion of valve springs within the cylinder head assembly, which is required to provide access for grinding the valves and the valve seats. in U.S. Pat. No. 3,742,579 Oftedahl describes an elaborate apparatus for supporting the six cylinders of an aircraft internal combustion engine, rotating these cylinders to facilitate the grinding of valves and valve seats, and a valve restraining device for use in installing the valve spring. The Oftedahl devices uses two opposing plates which simultaneously engage the flanged base sections of all six cylinder assemblies. These plates are secured to the frame section by multiple studs and wingnuts. The Oftedahl device is unnecessarily complicated and expensive because it is designed to simultaneously hold all six cylinder assemblies, whereas the mechanic can work only on one cylinder assembly at a time. Also, the Oftedahl device discloses no method for preventing the marring or scratching of the valves, the cylinder head or the cylinder sleeve assembly.
In a related device, Krogman, in U.S. Pat. No. 1,697,921, discloses a repair stand having a valve supporting bar which extends longitudinally beneath the center portion of the cylinder head and thereby prevents the valves from decoupling from the head when the valve springs are removed.